Former Prime Minister Manmohan Singh was admitted to AIIMS New Delhi Sunday night after he complained of uneasiness and was under observation of doctors.
Singh, 87, was taken to AIIMS Cardiac Care Unit and doctors said they were observing his condition.
He was later shifted to a private room and remains under observation.
Sources said the former PM complained of uneasiness and was advised to get medics care at AIIMS.
Earlier in 2009, he had undergone a coronary artery bypass surgery by a team of surgeons led by cardio-thoracic surgeon Ramakant Panda at AIIMS.
Singh is a senior leader of the opposition Congress and currently represents Rajasthan in the Upper House of Parliament. He was the Prime Minister between 2004 and 2014.
Rajasthan chief minister Ashok Gehlot expressed concern over the health of former Prime Minister Manmohan Singh.
“Much worried to know former PM Dr Manmohan Singh ji has been admitted to AIIMS. I wish him speedy recovery and pray for his good health and long life,” Gehlot tweeted.